Many peptides and proteins are attractive as drug candidates, due to their high bioactivities and receptor selectivities. Peptide and protein drugs are usually administered by injections and this can lead to low patient compliance. Alternative routes of delivery are therefore in demand. Delivery by the pulmonary or oral routes is possible, but usually complicated by low bioavailability due to high proteolytic activity in the relevant organs, and due to low absorption through the relevant tissue. Furthermore, in the human body, peptide and protein drugs are often eliminated quickly from the circulation by proteolytic activity or by elimination via the kidney or liver. It is, therefore, generally desired or necessary to manipulate the drug by formulation or derivatization in order to achieve suitable in vivo half-life.
The object of this invention is to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.
An aspect of this invention is to improve the absorption of insulins through human tissues.
Another aspect of this invention is to improve the in vivo half-life of insulins.
Another aspect of this invention is to find insulins having a satisfactory physical stability.
Another aspect of this invention is to find insulins having a satisfactory chemical stability.
Another aspect of this invention is to find insulins having a satisfactory proteolytic stability.
Another aspect of this invention is to find insulins having a satisfactory solubility.